1. Field of the Invention
The present invention relates to a method and device for coupling an inflatable cushion to a reaction housing in an inflatable restraint system. 2. Related Art
In co-pending application Ser. No. 07/993,280, filed Dec. 18, 1992 by Lauritzen et al., now allowed U.S. Pat. No. 5,344,182 issued Sep. 6, 1994, which is owned by the assignee of the present invention, a system and method is disclosed for attaching an inflatable cushion to a reaction housing employed in an air bag module. The system employs a metal cushion retainer member as an interface between the gas inlet opening of an inflatable cushion and the reaction housing. Among other advantages, the retainer member serves as a structural brace or cross-tie for holding the walls of the reaction housing together. The cushion retainer member generally includes a pair of cylindrical channel portions that are separated by spacers (FIG. 4) into which a corresponding pair of thickened peripheral gas inlet openings of an inflatable cushion is inserted (FIG. 3). The thickened gas inlet opening is formed by providing a channel member, typically in the form of a hem, about the gas inlet opening of the cushion into which a bead material, such as a plastic rod, is inserted. Once formed, the thickened gas inlet opening, which is referred to herein as an "inflatable cushion insert" or simply "cushion insert" is placed into the respective channel portion of the cushion retainer.
The channel portion of the retainer member is typically in the form of a cylindrical sleeve having an elongate slot extending along its length to accommodate receipt of the hem or channel member of the inflatable cushion. Once the cushion insert is placed into the channel portion of the retainer, it is compressed about the flanged cushion insert in a crimping operation to form an attachment insert which is referred to hereinafter as a cushion retainer insert. The latter insert is then incorporated into an attachment sleeve of the reaction housing for the fastenerless attachment of the inflatable cushion thereto.
The use of a plastic rod in the hem of the gas inlet opening of the cushion facilitates the equal distribution of stresses on the cushion during its deployment. Unfortunately, during handling and assembly of the cushion insert into the inflatable restraint system, the rod has a tendency to fall out of its channel member or hem, thereby making the assembly process a sometimes awkward and cumbersome operation and necessitating the use of human intervention. Commonly owned copending application Ser. No. 08/289,868 filed concurrently with the present application on Aug. 12, 1994, now U.S. Pat. No. 5,454,588, addresses this situation by providing a means for retaining the rod in the channel member of the cushion in the form of a flange to provide what is termed as a flanged cushion insert.
Since the channel portion of the cushion retainer member is radially compressed about the flanged cushion insert, such as by a crimping operation, the compression is not always done in a uniform manner. For example, the compression can be overdone which will produce a smaller cross sectional area for the retainer insert and cause it to be loosely contained within the rigid attachment sleeve of the reaction housing member. A separate device or machine is therefore required to not only provide uniform securement of the cushion insert within the cushion retainer member, but also to align and couple the cushion retainer insert with the attachment sleeve of the reaction housing after the compression step. In order to improve the economics of the cushion insert assembly process, a method and device has now been provided whereby the alignment and securement of the retainer insert, or for that matter the cushion insert itself, with the reaction housing can be effected simultaneously. This is accomplished by placing the respective insert into an appropriately configured tool that provides for uniform compression of the channel portion of the retainer member about the insert, and at the same time aligns the resulting insert with the attachment sleeve of the reaction housing for automatically coupling the inflatable cushion with the reaction housing.
U.S. Pat. No. 3,304,602 issued to Osborne on Feb. 21, 1967 discloses a tool for clamping ferrules to cords of nonmetallic material. The tool is a pin and die arrangement wherein the die has a conical aperture of circular cross section whose sides slope downwardly and inwardly to a smaller circular cross section for axially and slidably receiving a pin therethrough. A guide is provided in the form of a cap mounted to the top of the die and having a cylindrically shaped opening for receiving the pin therethrough. Once the ferrule, whose width is greater than the small end of the aperture, is positioned about a cord and loosely seated into the conical aperture of the die, the top of the pin extending through the top of the cap is struck with a hammer to force the ferrule downwardly through the narrow opening of the aperture, thereby clamping the ferrule about the cord. However, the die of the tool would not be adaptable for the clamping of a cylindrically shaped sleeve of a cushion retainer member about a cushion insert since no elongate slot is provided in the die that would accommodate the passage of a cushion insert and accompanying inflatable cushion, through the die.